ang Qi

Col6a1 Polymorphisms Associated With Ossification of the Ligamentum Flavum and Ossification of the Posterior Longitudinal Ligament

Study Design. A case–control association study was conducted to investigate the genetic etiology for ossification of the ligamentum flavum (OLF) and ossification of the posterior longitudinal ligament of the spine (OPLL). Objective. To determine whether COL6A1 polymorphisms are associated with susceptibility to OLF and OPLL in Chinese Han population. Summary of Background Data. The COL6A1 has been identified as a susceptibility gene for OPLL in Japanese. The susceptibility gene for OPLL may be different among various populations, so we investigated whether COL6A1 polymorphisms are also associated with OPLL in Chinese Han population. OLF and OPLL are similar in epidemiology, etiology, and pathology, and common coexist. Hereditary factors may be implicated in OLF and COL6A1 may be a potential susceptibility gene for OLF, so we investigated the relations between COL6A1 polymorphisms and OLF. Methods. Four known single nucleotide polymorphisms (SNPs) of COL6A1 were genotyped among 338 Chinese Han subjects by high throughput GenomeLab SNPstream genotyping system. Allele frequency and genotype distribution of each polymorphism were compared using a contingency &khgr;2 test between 183 cases (90 OPLL, 61 OLF, and 32 OPLL coexisting with OLF) and 155 controls. Results. Among 4 studied SNPs, allele frequency of promoter (−572T) SNP demonstrated the most significant difference not only between OPLL cases and controls (P = 2.65E-4), but also between OLF cases and controls (P =7.38E-4). Moreover, the overall frequency of haplotypes constructed from promoter (−572), intron 32 (−29), and intron 33 (+20) SNPs showed significant difference not only between the patients with OPLL and controls, but also between the patients with OLF and controls (P = 5.86E-3, P = 1.5E-8, respectively). Conclusion. This is the first report on SNPs of COL6A1 in OLF that suggests polymorphisms may be a risk factor for OLF. Our findings indicate that COL6A1 may be a common susceptibility gene for OLF and OPLL in Chinese Han population.

The frequency and treatment of dural tears and cerebrospinal fluid leakage in 266 patients with thoracic myelopathy caused by ossification of the ligamentum flavum.

Study Design. Retrospective review. Objective. To perform a single-institution analysis of incidence, treatment, and clinical outcome in patients with thoracic ossification of the ligamentum flavum (OLF) who experienced dural tears and cerebrospinal fluid (CSF) leakage. Summary of Background Data. There is a paucity of clinical reports focusing on dural tears and CSF leakage after thoracic OLF surgery. Because dural adhesion and dural ossification are common features of thoracic OLF, the incidence of CSF leakage in OLF patients is high and represents a significant clinical challenge. Methods. A total of 266 patients with thoracic OLF were admitted to our hospital from 1995 to 2011. Each patients medical records were reviewed to identify cases of dural tears and CSF leakage. Information on therapeutic strategy used to repair the dural tears and complications related to CSF leakage was extracted. Results. The incidence of dural tears and CSF leakage in OLF patients was 32% (85/266). The incidence of dural ossification was 25.2%. The dural tears were repaired with a range of materials, including gelatin sponge, muscle/fascia, artificial dura, silk suture, and fibrin glue. The intraoperative repair procedure did not resolve CSF leakage in 65 cases, and 16 of those cases experienced complications related to the continued CSF leakage, including CSF pseudocyst, wound dehiscence, and meningitis. Fifty-eight patients with CSF leakage were eventually cured by a series of comprehensive treatments, which included prone position, continuous pressure by sandbag, ultrasound-guided puncture, and aspiration. Only 7 patients required reoperation. Conclusion. Dural ossification was the main reason for dural tears. In all, 78 of the 85 patients with CSF leakage or dural tear were successfully cured. The success rate was 91.8%, which indicated that a series of comprehensive treatments was an effective strategy to treat these patients.

Clinical Features of Thoracic Spinal Stenosis-associated Myelopathy: A Retrospective Analysis of 427 Cases.

Study Design:This was a retrospective review. Objective:The aim of this study was to examine the epidemiological characteristics and causes of spinal cord compression in thoracic spinal stenosis (TSS). Summary of Background Data:As the thoracic spinal canal is relatively narrow and the thoracic cord has a poor blood supply, severe neurological symptoms may develop if TSS is not treated promptly. However, as it is rare, TSS is less often studied and its clinical features are often not recognized. Methods:Between 2005 and 2012, 427 patients diagnosed with TSS underwent surgery in our department. The male to female ratio was 1.4:1. The mean age was 53 years. The most reported symptom was motor deficit in the lower extremities (347 cases, 81%), followed by sensory deficit in the lower limbs (271 cases, 64%). Falls were the most common trigger of acute symptoms (29 cases, 7%). Preoperative imaging results of each case were reviewed to summarize the causes and site of cord compression and coexisting spinal diseases. Results:The most reported compressive factor was ossification of the ligamentum flavum (OLF), which implicated in 309 cases, followed by thoracic disk herniation (TDH) and ossification of the posterior longitudinal ligament (OPLL). The most common site of OLF and TDH was T9–L1 (56% and 89%, respectively), whereas OPLL was mainly found at T1–8 (90%). Forty-seven patients (11%) had coexisting lumbar spinal disease and 64 (15%) had cervical disease. Conclusions:Onset of TSS was generally insidious but may be triggered acutely by apparently trivial events. Myelopathy mainly affected the lower limbs. The most common cause was OLF in the lower thoracic spine. Cervical or lumbar spinal disease was often also evident; therefore, comprehensive clinical assessment is required to avoid delays in diagnosis and treatment.

Analysis of spinopelvic sagittal alignment in patients with thoracic and thoracolumbar angular kyphosis.

Study Design. Retrospective and radiological analysis of spinopelvic sagittal alignment in Chinese patients with thoracic and thoracolumbar kyphosis. Objective. To determine the impact of thoracic and thoracolumbar kyphosis on pelvic sagittal morphology and the mechanisms of adjusting trunk sagittal balance. Summary of Background Data. Previous studies have reported the normative values of pelvic sagittal parameters and classification of normal patterns of sagittal curvature, but no study has analyzed the impact of thoracic and thoracolumbar kyphosis on pelvic sagittal morphology and the mechanisms of maintaining the sagittal balance. Methods. Whole spine and standing lateral radiographs of 49 Chinese patients with thoracic and thoracolumbar kyphosis were obtained before surgery, immediately after surgery, and in the final follow-up. The pelvic and spinal parameters were measured and the correlations of all parameters were analyzed. A descriptive analysis characterizing these parameters and a multivariate analysis were performed. Results. The patients had a mean age of 30.3 years, whereas the mean age at which the patients who developed kyphosis was 7.1 years. Preoperative pelvic incidence was significantly less than that of normal subjects, and there was no difference in the preoperative, in the immediate postoperative, and in the final follow-up radiographs. The magnitude of kyphosis and the levels involved were independent factors of pelvic incidence. Pelvis anteversion and lumbar hyperlordosis were the mechanisms of adjusting the trunk sagittal balance. Although kyphosis and sagittal imbalance was corrected by surgery, pelvic sagittal morphology remained unchanged. Conclusion. Thoracic and thoracolumbar angular kyphosis occurring during the growth period will lead to abnormal pelvic morphology. The greater the kyphotic angle and lower the kyphotic levels, the greater the impact on the pelvic morphology during skeletal maturation. The mechanisms of adjusting the trunk sagittal balance not only include pelvis anteverting, but also lumbar hyperlordosis. The latter serves as the main mechanism once skeletal maturation has been established. After skeletal maturation, surgery can re-establish the spinal sagittal balance but not the pelvis morphology. Level of Evidence: 3

Clinical and radiographic evaluation of posterior surgical correction for the treatment of moderate to severe post-tuberculosis kyphosis in 36 cases with a minimum 2-year follow-up

OBJECT The object of this study was to compare the clinical and radiographic outcomes of 36 patients with posttuberculosis kyphosis who underwent one of two types of osteotomy. METHODS Each patient underwent single-stage correction via a posterior surgical approach. A modified pedicle subtraction osteotomy (mPSO) was performed when the kyphotic deformity was less than 70° (7 cases), whereas a posterior vertebral column resection (VCR) was performed when the kyphotic deformity exceeded 70° (29 cases). Full-length standing radiographs were obtained before surgery and at follow-up visits. These images were used to measure the kyphosis angle; sagittal alignment of the lumbar, thoracic, and cervical regions; and sagittal balance of the spine. Back pain was rated using the visual analog scale (VAS), and neurological function was classified based on the American Spinal Injury Association (ASIA) grading system. Each patients overall satisfaction with surgical treatment was measured with the Patient Satisfaction Index. For purposes of comparison, patients were studied in 2 groups based on the region of their kyphotic apex. Half of the cohort had apical kyphosis in the lower thoracic spine or thoracolumbar junction (TL group). Using both radiographic and clinical assessments, the authors compared this group with the other half of the patients who had apical kyphosis in the upper to mid thoracic spine (MT group). RESULTS The cohort included 15 males and 21 females, with an average age of 34 years at the time of surgery. The minimum follow-up was 24 months, and the mean follow-up was 31 months. Following surgery, kyphosis across the treated segments was reduced by an average of 60°. Lumbar lordosis also improved by an average of 24°, and thoracic kyphosis improved by an average of 20°. Both back pain and neurological function improved after surgical treatment. There was a 67% improvement in VAS scores, and 13 of the 36 patients had improvement in their ASIA grade. The 2 surgical procedures used for deformity correction (mPSO and VCR) demonstrated comparable radiographic and clinical results. Note, however, that differences were found in both radiographic and clinical outcomes in comparing patients who had lower thoracic or thoracolumbar (TL group) versus upper to midthoracic (MT group) apical kyphosis. CONCLUSIONS Posterior tubercular kyphosis can be effectively improved through corrective surgery, and deformity correction can be accompanied by improvement in clinical symptoms. When appropriately selected, both the mPSO and the VCR can be expected to yield satisfactory reduction of post-tuberculosis kyphotic deformities. Differences in radiographic and clinical outcomes should be anticipated, however, when treating such deformities in different regions of the spine.

Complications of correction for focal kyphosis after posterior osteotomy and the corresponding management.

Study Design: A clinical retrospective study. Objective: To analyze the complications and relevant management of the correction procedure for focal kyphosis. Summary of Background Data: The treatment of focal kyphosis is a difficult problem in spine surgery. The potential complications of surgery should be considered cautiously and managed positively. Methods: Eighty-one patients with focal kyphosis were treated by posterior osteotomy and correction. The etiology was posttraumatic in 31 cases, healed tuberculosis in 31 cases, congenital in 17 cases, and iatrogenic in 2 cases. The surgical procedures were pedicle subtraction osteotomy in 19 cases, posterior osteotomy with anterior opening-posterior closing correction in 23 cases, and posterior vertebral column resection with dual axial rotation correction in 39 cases. The intraoperative and postoperative complications were summarized, and the corresponding management was described in detail. Results: The average follow-up time was 31 months. Among patients who underwent pedicle subtraction osteotomy, the intraoperative and postoperative complications included 3 cases of dural tear and 1 case of wound infection. For posterior osteotomy with anterior opening-posterior closing correction, the complications included 4 cases of dural tear, 1 case of wound infection, and 1 case of instrumentation loosening and recurrence of kyphosis . For posterior vertebral column resection with dual axial rotation correction, the complications included 3 cases of dural tear, 5 cases of nerve root injury, 1 case of titanium mesh loosening, 1 case of osteotomy segment migration, 2 cases of transient neurological compromise, and 1 case of instrumentation loosening and kyphosis recurrence. All the complications were treated positively and pertinently. Conclusions: During the posterior osteotomy and correction of focal kyphosis, the risk of surgery increases along with the more severe deformity and the more complicated surgical procedure. However, most complications do not significantly affect the outcome if treated appropriately.

Diagnosis and treatment of ossification of the ligamentum flavum associated with dural ossification: clinical article.

OBJECT In this paper, the authors aimed to summarize the clinical characteristics of ossification of the ligamentum flavum (OLF) associated with dural ossification (DO) and to identify improved methods for preoperative diagnosis. METHODS Thirty-six patients who had undergone OLF surgery between February 2005 and September 2009 were included in this retrospective study. The patients were divided into 2 groups: one that included patients with intraoperative evidence of DO and a second group that included patients without DO. The clinical features of DO were summarized and the neurological status of the patients was evaluated pre- and postoperatively. RESULTS The incidence rate of DO associated with OLF was 39% (14/36). The sensitivity and specificity of the tram track sign were found to be 93% and 59%, respectively. Dural ossification was found among 86% of the patients with tuberous type Sato classification. The postoperative neurological status of patients was generally improved relative to that observed prior to surgery, although neurological recovery did not differ between the 2 groups. Cerebrospinal fluid leakage was the main complication, occurring predominantly in the patients with DO, and all leaks resolved in all patients after comprehensive treatments. CONCLUSIONS The tram track sign and Sato classification were found to be useful for preoperative diagnosis of DO and for determining the surgical procedure to be performed. Dural ossification had no effect on postoperative neurological recovery.

Posterior surgical correction of posttraumatic kyphosis of the thoracolumbar segment.

Objectives: To analyze the clinical characteristics and surgical results of posttraumatic kyphosis of the thoracolumbar segment. Methods: Thirty-four patients with posttraumatic kyphosis of the thoracolumbar segment underwent posterior osteotomy, kyphosis correction, and fixation at our hospital. The kyphosis apex was from T10 to L2. There were 15 male and 19 female patients. The mean age was 48.9 years. Full-spine standing radiographs were obtained before surgery, after surgery, and at follow-up. The sagittal spine balance status was evaluated, and the kyphotic angle, the lumbar lordotic angle, and the thoracic kyphotic angle were measured. The Frankel grading system for neurological functions and the Visual Analogue Scale for back pain were evaluated before surgery and at follow-up. The Oswestry Disability Index was applied for assessment of life quality and surgical results of patients. The Patient Satisfied Index (PSI) was also used for determination of surgical results. Patients were grouped according to the extent of kyphotic angle and the surgical technique. The difference in kyphosis correction and back pain between groups was observed before and after surgery. Relief from neurological symptoms was also observed. Results: The average kyphotic angle was 48.5 degrees, the average lumbar lordotic angle was 57.9 degrees, and the average thoracic kyphotic angle was 11.4 degrees before surgery. The sagittal spine balance was well maintained in 14 cases, and negative imbalance and positive imbalance were seen in 13 cases and 7 cases, respectively. There was significant difference in back pain between patients in the abnormal and normal groups of the lumbar lordotic angle. The average follow-up time after surgery was 32.1 months. The average kyphotic angle correction rate was 90.4% after surgery and 87.2% at follow-up. The average Oswestry Disability Index was 50.4% before surgery, which improved to 29.4% at follow-up, with an improvement rate of 41.5%. The Patient Satisfied Index result showed a total satisfactory rate of 94.1%. There were 16 cases of neurological deficit before surgery; 8 of them achieved various degrees of improvement after surgery. Conclusions: Surgical correction of posttraumatic kyphosis of the thoracolumbar segment can show good radiologic and clinical results with the appropriate procedure according to the extent of the kyphosis angle. Some patients with neurological deficit are still worthy of surgical treatment.

MiR‐199b‐5p inhibits osteogenic differentiation in ligamentum flavum cells by targeting JAG1 and modulating the Notch signalling pathway

Ossification of the ligamentum flavum (OLF) is a pathology almost only reported in East Asian countries. The leading cause of OLF is thoracic spinal canal stenosis and myelopathy. In this study, the role of miR‐199b‐5p and jagged 1 (JAG1) in primary ligamentum flavum cell osteogenesis was examined. MiR‐199b‐5p was found to be down‐regulated during osteogenic differentiation in ligamentum flavum cells, while miR‐199b‐5p overexpression inhibited osteogenic differentiation. In addition, JAG1 was found to be up‐regulated during osteogenic differentiation in ligamentum flavum cells, while JAG1 knockdown via RNA interference caused an inhibition of Notch signalling and osteogenic differentiation. Moreover, target prediction analysis and dual luciferase reporter assays supported the notion that JAG1 was a direct target of miR‐199b‐5p, with miR‐199b‐5p found to down‐regulate both JAG1 and Notch. Further, JAG1 knockdown was demonstrated to block the effect of miR‐199b‐5p inhibition. These findings imply that miR‐199b‐5p performs an inhibitory role in osteogenic differentiation in ligamentum flavum cells by potentially targeting JAG1 and influencing the Notch signalling pathway.

Polymicrobial and Monomicrobial Infections after Spinal Surgery: A Retrospective Study to Determine which Infection is more Severe

Study Design A retrospective clinical review. Purpose To investigate the difference in clinical manifestations and severity between polymicrobial and monomicrobial infections after spinal surgery. Overview of Literature Surgical site infections (SSIs) after spinal surgery are a major diagnostic and therapeutic challenge for spinal surgeons. Polymicrobial infections after spinal surgery seem to result in poorer outcomes than monomicrobial infections because of complementary resistance to antibiotics. However, comparison of the clinical manifestations and severity between polymicrobial and monomicrobial infections are limited. Methods Sixty-seven patients with SSIs after spinal surgery were studied: 20 patients with polymicrobial infections and 47 with monomicrobial infections. Pathogenic bacteria identified were counted and classified. Age, sex, and body mass index were compared between the two groups to identify homogeneity. The groups were compared for clinical manifestations by surgical site, postoperative time to infection, infection site, incisional drainage, incisional swelling, incisional pain, neurological signs, temperature, white blood cell count, and the percentage of neutrophils. Finally, the groups were compared for severity by hospital stay, number of rehospitalizations, number of debridements, duration of antibiotics administration, number of antibiotics administered, and implant removal. Results Polymicrobial infections comprised 29.9% of SSIs after spinal surgery, and most polymicrobial infections (70.0%) were caused by two species of bacteria only. There was no difference between the groups in terms of clinical manifestations and severity. In total, 96 bacterial strains were isolated from the spinal wounds: 60 strains were gram-positive and 36 were gram-negative pathogenic bacteria. Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Enterobacter cloacae were cultured in order of the frequency of appearance. Conclusions Most polymicrobial infections were caused by two bacterial species after spinal surgery. There was no difference in clinical manifestations or severity between polymicrobial and monomicrobial infections.